Main girder of single-girder crane

Abstract

The invention relates to an improved structure of a main girder of a crane and especially to a main girder of a single-girder crane. The main girder comprises an upper bearing plate, a lower bearing plate and two symmetrical special-shaped side plates; reinforcing plates are fixed in an inner cavity of a main girder body along a transverse direction at intervals; the cross section of the main girder is an approximate combined section, the upper part of the section is a rectangle with a bottom opening, the middle part of the section is a reversed isosceles trapezoid with a top opening and a bottom opening, the lower part of the section is a rectangle with a top opening, and the length and the width of the rectangle with a bottom opening at the upper part are respectively greater than the length and the width of the rectangle with a top opening at the lower part; the width of the upper bearing plate is greater than the maximum width between the two side plates, the width of the lower bearing plate is greater than the minimum width between the two side plates but smaller than the maximum width between the two side plates, the thickness of the upper bearing plate is greater than or equal to the thickness of the two side plates, and the thickness of the lower bearing plate is greater than the thickness of the two side plates. The main girder provided in the invention has a simple structure, is easy to manufacture and process, enables manufacture cost to be reduced and production efficiency to be improved and is especially applicable to flow line production; in the process of manufacturing the main girder, the problem of camber of the main girder of a crane is easily overcome, and the service life of the crane is prolonged, so the main girder can be easily popularized and applied.

Description

technical field [0001] The invention relates to an improved structure of a main girder of a crane, in particular to a main girder of a single girder crane. Background technique [0002] At present, there are generally two main girder structures of electric single-girder cranes and hoist gantry cranes (such as figure 1 , figure 2 As shown), one is to use the steel plate to roll into a U-shaped groove, weld the supporting ribs in the U-shaped groove, then weld the I-beam and the ribs, and finally weld the I-beam and the U-shaped groove together with the side plate , the production method has more butt welds; both the U-shaped groove and the side plate need to be cold-formed or calendered. Since the main beam requires a certain degree of camber according to the current national standard, the U-shaped groove must be formed during the tailor-welded combination For a certain camber, the I-beam also needs to be formed by cold bending or flame heating; and because of the position...

AI Technical Summary

Problems solved by technology

Through the method of cold-bending the steel plate, although the welding seam of the main girder of the crane can be reduced to two and the camber problem of the main girder is solved, the following problems are found in the structure during the manufacturing process: 1. When the main girder is cold The height after bending is too large, for example, when the height exceeds 700mm, the welding conditions of the internal ribs of the box girder are poor

2. The steel plate forming process of the box-type main girder is relatively cumbersome. When using presses and bending machines for forming, the production efficiency is relatively low due to the limitation of equipment conditions. investment is too high

3. When the lifting capacity or span is large, the width of the main girder box steel plate required is relatively large, and tailor welding of the steel plate is still required

4. During the production of the main girder, because it is a steel plate that is cold-formed as a whole, it is greatly restricted by the current mass-produced steel plate specifications, and there is a problem of high scrap rate for some width steel plates

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